A rigid tank of volume $50 \text{ m}^{3}$ contains a pure substance as a saturated liquid vapour mixture at $\text{400 kPa}$. Of the total mass of the mixture, $20\%$ mass is liquid and $80\%$ mass is vapour. Properties at $\text{400 kPa}$ are: $T_{sat} = 143.61 ^{\circ}C$, $v_{f} = 0.001084\:\text{m$^{3}$/kg}$, $v_{g} = 0.46242\:\text{m$^{3}$/kg}$. The total mass of liquid vapour mixture in the tank is _______  $\text{kg } (\textit{round off to the nearest integer}$).